Gemini near-infrared imager

We discuss the main design features of the Gemini Near-IR Imager (NIRI) and its scientific capabilities. NIRI is designed to fully exploit the excellent image quality and low telescope emissivity expected from the Gemini telescope on Mauna Kea. It offers a range of pixel scales matched to different scientific objectives and has spectroscopic as well as polarimetric capabilities. One of its main design features is the use of a near-IR 2 X 2 Shack-Hartmann wavefront sensor for tip-tilt and focus control.